About this replacement
Acer Swift 3 SF314-57G-7448 — 11.25V Li-Polymer Replacement Battery (AP18C8K)
This is an 11.25V, 4450mAh (50.06Wh) Li-Polymer battery for the Acer Swift 3 and Chromebook 314 series. It replaces OEM part AP18C8K and fits models including the SF314-57G-7448, SF314-58G-72FD, SF314-57G-59V7, and Chromebook 314 C933-C2QR. If your original cell has swelled, dropped capacity, or stopped holding a charge, this is the direct replacement.
- Swift 3 and Chromebook 314 compatibility: These models share the same 11.25V three-cell rail, AP18C8K connector pinout, and BMS communication protocol — so one cell fits across the full production run without modification.
- Bench tested on actual hardware: We ran this cell through charge, discharge, and BMS handshake verification on the SF314 platform. The BMS accepted the cell without fault codes, and the charge controller stepped through CC/CV phases correctly on both AC adapters tested.
- Post-install calibration for the SF314 platform: After fitting, run the laptop down to hibernate-cutoff on battery only — no AC — then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap.
Why the Swift 3 BIOS reports poor battery health after a cell swap
The Acer BIOS reads stored EEPROM data from the battery management IC to determine health status. When a new cell is installed, the EEPROM contains factory baseline figures that do not yet match actual cell behaviour under load. The BIOS flags this mismatch as degraded or unknown health — it is a calibration state, not a fault. One full discharge-to-hibernate followed by an uninterrupted charge cycle rewrites the fuel gauge IC's reference data and clears the warning.
Swift 3 shutting down at 20–30% remaining charge shown on screen
This happens when the fuel gauge IC has not yet calibrated against the new cell's voltage curve. The reported percentage stays high while actual cell voltage drops under combined CPU and display load, hitting the BMS low-voltage cutoff before the OS sees 0%. The fix is the same calibration cycle: discharge fully to hibernate on battery, then charge to 100% without interruption. After two or three cycles the gauge tracks the real voltage curve and the premature shutdowns stop.